"""Interval module: contains the Interval class"""

__all__ = ['Interval']

from panda3d.core import ClockObject, PStatCollector
from panda3d.direct import CInterval
from direct.directnotify.DirectNotifyGlobal import directNotify
from direct.showbase.DirectObject import DirectObject
from direct.showbase.MessengerGlobal import messenger
from direct.task.Task import Task, TaskManager
from direct.task.TaskManagerGlobal import taskMgr
from direct.extensions_native import CInterval_extensions # pylint: disable=unused-import
from direct.extensions_native import NodePath_extensions # pylint: disable=unused-import
import math


class Interval(DirectObject):
    """Interval class: Base class for timeline functionality"""

    # create Interval DirectNotify category
    notify = directNotify.newCategory("Interval")

    playbackCounter = 0

    # Class methods
    def __init__(self, name, duration, openEnded=1):
        self.name = name
        self.duration = max(duration, 0.0)
        self.state = CInterval.SInitial
        self.currT = 0.0
        self.doneEvent = None
        self.setTHooks = []
        self.__startT = 0
        self.__startTAtStart = 1
        self.__endT = duration
        self.__endTAtEnd = 1
        self.__playRate = 1.0
        self.__doLoop = 0
        self.__loopCount = 0

        self.pstats = None
        if __debug__ and TaskManager.taskTimerVerbose:
            self.pname = name.split('-', 1)[0]
            self.pstats = PStatCollector("App:Tasks:ivalLoop:%s" % (self.pname))

        # Set true if the interval should be invoked if it was
        # completely skipped over during initialize or finalize, false
        # if it should be ignored in this case.
        self.openEnded = openEnded

    def getName(self):
        return self.name

    def getDuration(self):
        return self.duration

    def getOpenEnded(self):
        return self.openEnded

    def setLoop(self, loop=1):
        self.__doLoop = loop

    def getLoop(self):
        return self.__doLoop

    def getState(self):
        return self.state

    def isPaused(self):
        return self.getState() == CInterval.SPaused

    def isStopped(self):
        # Returns true if the interval has not been started, has already
        # played to its completion, or has been explicitly stopped via
        # finish().
        return self.getState() == CInterval.SInitial or \
               self.getState() == CInterval.SFinal

    def setT(self, t):
        # There doesn't seem to be any reason to clamp this, and it
        # breaks looping intervals.  The interval code should properly
        # handle t values outside the proper range.
        #t = min(max(t, 0.0), self.getDuration())

        state = self.getState()
        if state == CInterval.SInitial:
            self.privInitialize(t)
            if self.isPlaying():
                self.setupResume()
            else:
                self.privInterrupt()
        elif state == CInterval.SStarted:
            # Support modifying t while the interval is playing.  We
            # assume is_playing() will be true in this state.
            assert self.isPlaying()
            self.privInterrupt()
            self.privStep(t)
            self.setupResume()
        elif state == CInterval.SPaused:
            # Support modifying t while the interval is paused.  In
            # this case, we simply step to the new value of t; but
            # this will change the state to S_started, so we must then
            # change it back to S_paused by hand (because we're still
            # paused).
            self.privStep(t)
            self.privInterrupt()
        elif state == CInterval.SFinal:
            self.privReverseInitialize(t)
            if self.isPlaying():
                self.setupResume()
            else:
                self.privInterrupt()
        else:
            self.notify.error("Invalid state: %s" % (state))
        self.privPostEvent()

    def getT(self):
        return self.currT

    def start(self, startT = 0.0, endT = -1.0, playRate = 1.0):
        """ Starts the interval.  Returns an awaitable. """
        self.setupPlay(startT, endT, playRate, 0)
        return self.__spawnTask()

    def loop(self, startT = 0.0, endT = -1.0, playRate = 1.0):
        self.setupPlay(startT, endT, playRate, 1)
        self.__spawnTask()

    def pause(self):
        if self.getState() == CInterval.SStarted:
            self.privInterrupt()
        self.privPostEvent()
        self.__removeTask()
        return self.getT()

    def resume(self, startT = None):
        if startT is not None:
            self.setT(startT)
        self.setupResume()
        if not self.isPlaying():
            self.__spawnTask()

    def resumeUntil(self, endT):
        duration = self.getDuration()

        if endT < 0 or endT >= duration:
            self.__endT = duration
            self.__endTAtEnd = 1
        else:
            self.__endT = endT
            self.__endTAtEnd = 0

        self.setupResume()
        if not self.isPlaying():
            self.__spawnTask()

    def finish(self):
        state = self.getState()
        if state == CInterval.SInitial:
            self.privInstant()
        elif state != CInterval.SFinal:
            self.privFinalize()
        self.privPostEvent()
        self.__removeTask()

    def clearToInitial(self):
        # This method resets the interval's internal state to the
        # initial state, abandoning any parts of the interval that
        # have not yet been called.  Calling it is like pausing the
        # interval and creating a new one in its place.
        self.pause()
        self.state = CInterval.SInitial
        self.currT = 0.0

    def isPlaying(self):
        return taskMgr.hasTaskNamed(self.getName() + '-play')

    def getPlayRate(self):
        """ Returns the play rate as set by the last call to start(),
        loop(), or setPlayRate(). """
        return self.__playRate

    def setPlayRate(self, playRate):
        """ Changes the play rate of the interval.  If the interval is
        already started, this changes its speed on-the-fly.  Note that
        since playRate is a parameter to start() and loop(), the next
        call to start() or loop() will reset this parameter. """

        if self.isPlaying():
            self.pause()
            self.__playRate = playRate
            self.resume()
        else:
            self.__playRate = playRate

    def setDoneEvent(self, event):
        self.doneEvent = event

    def getDoneEvent(self):
        return self.doneEvent

    def privDoEvent(self, t, event):
        if self.pstats:
            self.pstats.start()
        if event == CInterval.ETStep:
            self.privStep(t)
        elif event == CInterval.ETFinalize:
            self.privFinalize()
        elif event == CInterval.ETInterrupt:
            self.privInterrupt()
        elif event == CInterval.ETInstant:
            self.privInstant()
        elif event == CInterval.ETInitialize:
            self.privInitialize(t)
        elif event == CInterval.ETReverseFinalize:
            self.privReverseFinalize()
        elif event == CInterval.ETReverseInstant:
            self.privReverseInstant()
        elif event == CInterval.ETReverseInitialize:
            self.privReverseInitialize(t)
        else:
            self.notify.error('Invalid event type: %s' % (event))
        if self.pstats:
            self.pstats.stop()


    def privInitialize(self, t):
        # Subclasses may redefine this function
        self.state = CInterval.SStarted
        self.privStep(t)

    def privInstant(self):
        # Subclasses may redefine this function
        self.state = CInterval.SStarted
        self.privStep(self.getDuration())
        self.state = CInterval.SFinal
        self.intervalDone()

    def privStep(self, t):
        # Subclasses may redefine this function
        self.state = CInterval.SStarted
        self.currT = t

    def privFinalize(self):
        # Subclasses may redefine this function
        self.privStep(self.getDuration())
        self.state = CInterval.SFinal
        self.intervalDone()

    def privReverseInitialize(self, t):
        # Subclasses may redefine this function
        self.state = CInterval.SStarted
        self.privStep(t)

    def privReverseInstant(self):
        # Subclasses may redefine this function
        self.state = CInterval.SStarted
        self.privStep(0)
        self.state = CInterval.SInitial

    def privReverseFinalize(self):
        # Subclasses may redefine this function
        self.privStep(0)
        self.state = CInterval.SInitial

    def privInterrupt(self):
        # Subclasses may redefine this function
        self.state = CInterval.SPaused

    def intervalDone(self):
        # Subclasses should call this when the interval transitions to
        # its final state.
        if self.doneEvent:
            messenger.send(self.doneEvent)

    def setupPlay(self, startT, endT, playRate, doLoop):
        duration = self.getDuration()

        if startT <= 0:
            self.__startT = 0
            self.__startTAtStart = 1
        elif startT > duration:
            self.__startT = duration
            self.__startTAtStart = 0
        else:
            self.__startT = startT
            self.__startTAtStart = 0

        if endT < 0 or endT >= duration:
            self.__endT = duration
            self.__endTAtEnd = 1
        else:
            self.__endT = endT
            self.__endTAtEnd = 0

        self.__clockStart = ClockObject.getGlobalClock().getFrameTime()
        self.__playRate = playRate
        self.__doLoop = doLoop
        self.__loopCount = 0

    def setupResume(self):
        now = ClockObject.getGlobalClock().getFrameTime()
        if self.__playRate > 0:
            self.__clockStart = now - ((self.getT() - self.__startT) / self.__playRate)
        elif self.__playRate < 0:
            self.__clockStart = now - ((self.getT() - self.__endT) / self.__playRate)
        self.__loopCount = 0

    def stepPlay(self):
        now = ClockObject.getGlobalClock().getFrameTime()
        if self.__playRate >= 0:
            t = (now - self.__clockStart) * self.__playRate + self.__startT

            if self.__endTAtEnd:
                self.__endT = self.getDuration()

            if t < self.__endT:
                # In the middle of the interval, not a problem.
                if self.isStopped():
                    self.privInitialize(t)
                else:
                    self.privStep(t)

            else:
                # Past the ending point; time to finalize.
                if self.__endTAtEnd:
                    # Only finalize if the playback cycle includes the
                    # whole interval.
                    if self.isStopped():
                        if self.getOpenEnded() or self.__loopCount != 0:
                            self.privInstant()
                    else:
                        self.privFinalize()
                else:
                    if self.isStopped():
                        self.privInitialize(self.__endT)
                    else:
                        self.privStep(self.__endT)

                # Advance the clock for the next loop cycle.
                if self.__endT == self.__startT:
                    # If the interval has no length, we loop exactly once.
                    self.__loopCount += 1

                else:
                    # Otherwise, figure out how many loops we need to
                    # skip.
                    timePerLoop = (self.__endT - self.__startT) / self.__playRate
                    numLoops = math.floor((now - self.__clockStart) / timePerLoop)
                    self.__loopCount += numLoops
                    self.__clockStart += numLoops * timePerLoop

        else:
            # Playing backwards
            t = (now - self.__clockStart) * self.__playRate + self.__endT

            if t >= self.__startT:
                # In the middle of the interval, not a problem.
                if self.isStopped():
                    self.privInitialize(t)
                else:
                    self.privStep(t)
            else:
                # Past the ending point; time to finalize.
                if self.__startTAtStart:
                    # Only finalize if the playback cycle includes the
                    # whole interval.
                    if self.isStopped():
                        if self.getOpenEnded() or self.__loopCount != 0:
                            self.privReverseInstant()
                    else:
                        self.privReverseFinalize()
                else:
                    if self.isStopped():
                        self.privReverseInitialize(self.__startT)
                    else:
                        self.privStep(self.__startT)

                # Advance the clock for the next loop cycle.
                if self.__endT == self.__startT:
                    # If the interval has no length, we loop exactly once.
                    self.__loopCount += 1

                else:
                    # Otherwise, figure out how many loops we need to
                    # skip.
                    timePerLoop = (self.__endT - self.__startT) / -self.__playRate
                    numLoops = math.floor((now - self.__clockStart) / timePerLoop)
                    self.__loopCount += numLoops
                    self.__clockStart += numLoops * timePerLoop

        shouldContinue = (self.__loopCount == 0 or self.__doLoop)

        if (not shouldContinue and self.getState() == CInterval.SStarted):
            self.privInterrupt()

        return shouldContinue

    def __repr__(self, indent=0):
        space = ''
        for l in range(indent):
            space = space + ' '
        return space + self.name + ' dur: %.2f' % self.duration

    open_ended = property(getOpenEnded)
    stopped = property(isStopped)
    t = property(getT, setT)
    play_rate = property(getPlayRate, setPlayRate)
    done_event = property(getDoneEvent, setDoneEvent)

    # The rest of these methods are duplicates of functions defined
    # for the CInterval class via the file CInterval-extensions.py.

    def privPostEvent(self):
        # Call after calling any of the priv* methods to do any required
        # Python finishing steps.
        if self.pstats:
            self.pstats.start()
        t = self.getT()
        if hasattr(self, "setTHooks"):
            for func in self.setTHooks:
                func(t)
        if self.pstats:
            self.pstats.stop()

    def __spawnTask(self):
        # Spawn task
        self.__removeTask()
        taskName = self.getName() + '-play'
        task = Task(self.__playTask)
        task.interval = self
        taskMgr.add(task, taskName)
        return task

    def __removeTask(self):
        # Kill old task(s), including those from a similarly-named but
        # different interval.
        taskName = self.getName() + '-play'
        oldTasks = taskMgr.getTasksNamed(taskName)
        for task in oldTasks:
            if hasattr(task, "interval"):
                task.interval.privInterrupt()
                taskMgr.remove(task)

    def __playTask(self, task):
        again = self.stepPlay()
        self.privPostEvent()
        if again:
            return Task.cont
        else:
            return Task.done

    def popupControls(self, tl = None):
        """
        Popup control panel for interval.
        """
        # Don't use a regular import, to prevent ModuleFinder from picking
        # it up as a dependency when building a .p3d package.
        import importlib
        EntryScale = importlib.import_module('direct.tkwidgets.EntryScale')
        tkinter = importlib.import_module('tkinter')

        if tl is None:
            tl = tkinter.Toplevel()
            tl.title('Interval Controls')
        outerFrame = tkinter.Frame(tl)
        def entryScaleCommand(t, s=self):
            s.setT(t)
            s.pause()
        self.es = es = EntryScale.EntryScale(
            outerFrame, text = self.getName(),
            min = 0, max = math.floor(self.getDuration() * 100) / 100,
            command = entryScaleCommand)
        es.set(self.getT(), fCommand = 0)
        es.pack(expand = 1, fill = tkinter.X)
        bf = tkinter.Frame(outerFrame)
        # Jump to start and end
        def toStart(s=self, es=es):
            s.clearToInitial()
            es.set(0, fCommand = 0)
        def toEnd(s=self):
            s.pause()
            s.setT(s.getDuration())
            es.set(s.getDuration(), fCommand = 0)
            s.pause()
        jumpToStart = tkinter.Button(bf, text = '<<', command = toStart)
        # Stop/play buttons
        def doPlay(s=self, es=es):
            s.resume(es.get())

        stop = tkinter.Button(bf, text = 'Stop',
                      command = lambda s=self: s.pause())
        play = tkinter.Button(
            bf, text = 'Play',
            command = doPlay)
        jumpToEnd = tkinter.Button(bf, text = '>>', command = toEnd)
        jumpToStart.pack(side = tkinter.LEFT, expand = 1, fill = tkinter.X)
        play.pack(side = tkinter.LEFT, expand = 1, fill = tkinter.X)
        stop.pack(side = tkinter.LEFT, expand = 1, fill = tkinter.X)
        jumpToEnd.pack(side = tkinter.LEFT, expand = 1, fill = tkinter.X)
        bf.pack(expand = 1, fill = tkinter.X)
        outerFrame.pack(expand = 1, fill = tkinter.X)
        # Add function to update slider during setT calls
        def update(t, es=es):
            es.set(t, fCommand = 0)
        if not hasattr(self, "setTHooks"):
            self.setTHooks = []
        self.setTHooks.append(update)
        # Clear out function on destroy
        def onDestroy(e, s=self, u=update):
            if u in s.setTHooks:
                s.setTHooks.remove(u)
        tl.bind('<Destroy>', onDestroy)
